1. Field of the Invention
The field of invention generally relates to electronics and more particularly to a variable keeper strength process compensated dynamic circuit and method and a leakage current monitor circuit and method.
2. Background of the Related Art
The increasing leakage (e.g. current leakage in a transistor) in scaled technologies has forced designers to increase keeper sizes in dynamic circuits to obtain acceptable levels of robustness. However, the performance of dynamic circuits (e.g, wide-operating range (OR) gates) starts degrading with increasing keeper size. Register files and caches are particularly susceptible to this type of performance degradation, since wide-OR type dynamic circuits are often used in these types of circuits. Along with the increase in leakage, die-to-die (D2D) and within-die (WID) process variations cause the leakage distribution to become wider and wider. This process variation adversely affects the yield of usable dies obtained from a given manufacturing lot run.
Compared to previous technology generations, a significant portion of leaky dies may even fail with a strong keeper and low leakage dies may also suffer from the use of an unnecessarily strong keeper. A keeper is used to maintain a voltage level applied to a dynamic node stable. For example, a keeper may be used to hold a dynamic node to high when none of the pull down paths connected to the node are evaluating. In another example, a keeper may be used to hold a domino circuit high during clock stoppage and improve noise margins.
A flexible design technique and approach that uses a stronger keeper for the excess leakage dies and a relatively weaker keeper for low leakage dies can improve both overall robustness and performance. The problems and disadvantages in the related art are addressed and a process-compensated dynamic circuit and method are introduced using a variable strength keeper scheme to restore the robustness in excess leakage dies and avoid the performance loss and other penalties associated with low leakage dies.
Increasing the ultimate, final production yields from the production and manufacturing of integrated circuits and other electronic devices and components is another goal pursued by many companies in the quest for reducing costs and increasing production efficiencies. Some ways of achieving these goals are increasing the utilization rate of components produced in a given manufacturing lot is to develop and apply process compensation schemes, using as many devices from a given lot run as possible, by managing and compensating for the different component variances and implementing designs that are tolerant of these design variances.
There are different types of process compensation schemes in the related art. For example, process compensation schemes, such as adaptive body biasing and variable strength keeper based dynamic circuits are emerging design techniques where die-to-die (D2D) and within die (WID) parameter variations are deteriorating and becoming worse as scaling continues to increase. A common technical underpinning or theme behind these various process compensation techniques is the requirement of a method to accurately detect the process skew that is occuring.